CPT code 28715 – Triple arthrodesis of the foot

Key Takeaways

CPT code 28715 covers surgical fusion of all three hindfoot joints in a single operative session

The most common coding error: billing 28715 when only one or two joints were fused – use 28725 (subtalar only) or 28740 (two joints) instead

ICD-10 codes M21.4x (flatfoot/pes planus) and M19.07x (hindfoot osteoarthritis) are the primary diagnosis pairings

Pabau’s claims management workflow flags NCCI bundling conflicts and prior auth gaps before a claim leaves the practice

CPT code 28715: official description and procedure overview

CPT code 28715 carries the official AMA descriptor: Arthrodesis; triple. That two-word descriptor means the surgeon fuses three separate joints of the hindfoot in a single operative session.

The three joints involved are the subtalar (talocalcaneal), talonavicular, and calcaneocuboid joints. Together they control hindfoot inversion, eversion, and midfoot loading. When severe deformity, post-traumatic arthritis, or progressive flatfoot collapse makes conservative care inadequate, triple arthrodesis removes motion at all three joints, so the foot becomes stable and pain-free.

Key classification facts billers need at a glance:

• Code family: Musculoskeletal surgery, foot and toes (CPT 28700 series)
• Procedure type: Major open surgery – not minimally invasive, not arthroscopic
• Global period: 090 (90-day postoperative period)
• Bilateral indicator: Most payers apply modifier -50 rules; verify the current year Medicare Physician Fee Schedule indicator
• Typical setting: Hospital inpatient or ambulatory surgical center (ASC)

Procedure details: what surgeons do during a triple arthrodesis

Triple arthrodesis is performed through lateral and medial incisions. The lateral approach exposes the subtalar and calcaneocuboid joints; the medial approach gives access to the talonavicular joint. For audit purposes, the sequence in the operative report matters, because every joint must appear by name.

Standard steps documented in an audit-ready operative report:

1. Joint exposure: Lateral incision over the sinus tarsi; medial incision over the talonavicular joint
2. Cartilage removal: Articular cartilage excised from all three joint surfaces using osteotomes and curettes
3. Deformity correction: Hindfoot aligned to neutral; any valgus or varus deformity corrected before fixation
4. Bone grafting (if used): Autograft taken from the iliac crest (20902) or calcaneus, or allograft placed into joint gaps; harvest may be reported separately – confirm current NCCI edit pair status
5. Internal fixation: Cannulated screws, staples, or a combination placed across each joint under fluoroscopic guidance
6. Wound closure: Layered closure with drain placement as appropriate

The operative report must name all three joints as fused. However, if the surgeon addresses only two joints during surgery, 28715 does not apply – see the code comparison section below.

Covered and excluded services: what CPT 28715 includes

Several services are bundled into 28715 under NCCI edits. As a result, billing them separately without a valid modifier triggers a bundling denial.

CPT 28715 vs 28725, 28730, and 28740: how to choose the right code

The most frequent coding error on triple arthrodesis claims is selecting the wrong code from the 287xx arthrodesis series. In practice, the operative report’s joint count is the deciding factor.

Decision rule: Read the operative report. If the surgeon names and documents cartilage preparation and fixation at all three hindfoot joints, use 28715. If the talonavicular joint was not addressed, however, default to 28725. Likewise, if the operative site is midtarsal rather than hindfoot, consider 28730 or 28740.

ICD-10 diagnosis codes for CPT code 28715

Triple arthrodesis claims require a diagnosis code that shows medical necessity. In addition, payers and Medicare Administrative Contractors (MACs) publish Local Coverage Determinations (LCDs) specifying which ICD-10 codes they accept – always verify against the applicable LCD before submitting. The table below covers the most commonly paired codes; laterality suffixes (1 = right, 2 = left, 9 = unspecified) are mandatory on all applicable codes.

Unspecified laterality codes (e.g. M21.40) are valid only when the patient’s record does not state the side. Otherwise, payers expect the specific code. Submitting a bilateral claim with a unilateral code – or vice versa – is a common denial trigger.

Medicare and payer reimbursement for CPT 28715

CPT 28715 reimbursement varies by locality, facility vs. non-facility setting, and payer year. For this reason, practices should retrieve current figures from the CMS Physician Fee Schedule look-up tool rather than relying on static rate tables. Meanwhile, as a working reference, the FastRVU 2026 RVU look-up provides current Work, Practice Expense, and Malpractice RVU values by locality.

In general, billing teams should keep four reimbursement points in mind:

• Facility setting: Lower practice expense RVUs apply; the facility absorbs overhead costs
• Non-facility setting: Higher practice expense RVUs reflect in-office overhead; rarely used for this procedure
• Commercial payers: Rates typically exceed Medicare by 110-150%; confirm via payer contract
• Medicare Advantage: Plans negotiate separately; may apply Medicare fee schedule or apply own multipliers

Practices using electronic claims via Claim.MD can validate payer-specific fee schedules and run real-time eligibility checks before the claim is submitted, reducing the risk of submitting at the wrong rate or to the wrong payer contract. Building a clean claim from the outset is covered in detail in our guide to medical billing.

Automate your surgical billing workflow

Pabau’s claims management tools flag NCCI conflicts, track prior auth status, and route 28715 claims through Claim.MD before they reach the payer. Fewer denials, faster reimbursement.

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Prior authorization requirements for triple arthrodesis

Most commercial plans and Medicare Advantage programs require prior authorization for CPT 28715. Traditional Medicare (Parts A and B) does not require it for foot surgery. On the other hand, Medicaid requirements vary by state – always check the applicable state fee schedule and prior auth policy.

For example, reviewers typically request the following documents during the prior auth review:

• Imaging: weight-bearing X-rays, CT scan or MRI confirming joint destruction or deformity severity
• Conservative treatment failure: documented trial of orthotics, physical therapy, NSAIDs, and corticosteroid injections (usually 3-6 months minimum)
• Specialist notes: orthopaedic or podiatric surgeon evaluation confirming surgical candidacy
• Diagnosis codes: matching ICD-10 codes supporting medical necessity

If a prior auth is denied, appeal using the clinical record alongside peer-reviewed literature on triple arthrodesis outcomes. Tracking auth status before surgery is also part of broader medical billing compliance – practices that chase auth after scheduling a surgical date face avoidable write-offs.

Global surgery period and post-op billing for CPT 28715

CPT 28715 carries a 90-day global surgery period. All routine post-operative care within that window is bundled into the surgical fee – separate E&M billing for standard wound checks or cast changes is not payable during this period.

Even so, some services are separately reportable during the 90-day global window:

• Modifier -24: Unrelated evaluation and management visit during the global period
• Modifier -79: Unrelated procedure or service by the same physician during the global period
• Modifier -78: Return to the operating room for a complication related to the original procedure
• Modifier -58: Staged or related procedure during the postoperative period (planned before the initial surgery)

In addition, reviewing electronic remittance advice for 28715 claims helps identify global-period adjustment codes (CO-97, CO-58) early, so your team can correct modifier usage before the global window closes and the appeal deadline passes.

Modifiers commonly used with CPT 28715

Modifier choice affects both payment and audit risk. Therefore, the table below covers the modifiers most often applied to 28715 claims, with guidance on when each is appropriate.

CMS and commercial payers differ on bilateral surgery rules. For instance, under Medicare, modifier -50 on 28715 typically results in payment at 150% of the single-procedure rate. Commercial payers, on the other hand, may apply different multipliers or require separate line items with -LT and -RT instead. Confirm the payer’s bilateral payment policy in the contract or fee schedule before submitting.

Documentation requirements: what the operative report must include

An operative report that does not clearly document all three fused joints will trigger a downcode to 28725 or a denial on audit. For that reason, coders should not infer joint count from the diagnosis or approach – it must be stated in the body of the operative note.

Checklist for a 28715-compliant operative report, and guidance on clean claim requirements for surgical procedures:

• All three joints named explicitly: subtalar, talonavicular, and calcaneocuboid
• Approach documented: lateral incision (subtalar/calcaneocuboid) and medial incision (talonavicular)
• Cartilage removal described at each joint surface
• Deformity correction noted with intraoperative alignment achieved
• Fixation hardware specified: screw size, count, and joint placement
• Fluoroscopic guidance use noted (confirming it is bundled, not separately reported)
• Bone graft: source (autograft vs. allograft), harvest site if autograft
• Laterality: left or right foot clearly stated
• Surgeon attestation and timing

Consequently, practices with a structured surgical documentation workflow – where coders review the operative report against a pre-built 28715 checklist before claim submission – see far fewer post-payment audit adjustments than those relying solely on surgeon dictation without review.

Common claim denial reasons for CPT 28715 and how to avoid them

CPT 28715 claims fail for predictable reasons. Moreover, each denial reason below has a specific corrective action that prevents recurrence.

Practices that use structured denial management workflows – categorizing each denial by root cause and tracking appeal outcomes – resolve 28715 denials 30-40% faster than those working through remittances manually. As a result, Pabau’s claims management software surfaces NCCI edit conflicts and prior auth gaps before a claim reaches the payer, which tackles the two most common denial causes at the source.

Conclusion

Triple arthrodesis claims fail at a higher rate than most foot surgery codes because the 287xx series demands precision: wrong joint count, missing auth, or a bundling conflict each triggers a denial that takes weeks to appeal. Fortunately, the fix is a pre-submission checklist that confirms joint documentation, ICD-10 specificity, and modifier accuracy before the claim leaves the practice.

Pabau’s claims management tools also run NCCI edit checks and prior auth validation automatically, routing surgical claims through Claim.MD’s clearinghouse network so clean claims reach payers on the first submission. To see how the workflow handles high-value surgical codes like CPT 28715, book a demo.

Continue your research

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